Hyperfibrinogenaemia and hyperviscosity in sickle-cell crisis.

Plasma fibrinogen concentration and whole-blood viscosity, the latter measured at two shear rates (23 and 230 sec-1), were estimated during eight episodes of sickle-cell crisis and compared with values in 26 sickle-cell anaemia patients who were not in crisis. Painful crisis was associated with a significant increase in both plasma fibrinogen and whole-blood viscosity. Increased fibrinogen-erythrocyte interaction in vivo may be a significant contributory factor to raising blood viscosity and precipitating vaso-occlusive crisis in sickle-cell disease.

Fibrin-fibrinogen degradation products in cerebrospinal fluid.

An increase in low molecular weight fibrin-fibrinogen degradation products (FDP) was demonstrated in cerebrospinal fluid (CSF) from 17 of 18 patients with bacterial or viral meningitis compared with 29 patients without meningitis. The CSF also showed an increase in coagulation proteins of molecular weight less than 90000 (factors VII, IX, and plasminogen) but did not contain fibrinogen (MW 340000) or plasminogen activator. It is concluded that low molecular weight FDP in the CSF in infective meningitis result from leakage through a damaged blood-CSF barrier rather than from local digestion of fibrin deposited on the meninges.

The cytocentrifuge NBT test.

The NBT test is a non-specific test of neutrophil membrane stimulation which has application to the study of neutrophil function, particularly in the septicaemic patient. An improved cytochemical test which eliminates potential sources of laboratory error has been developed. Venous or capillary blood samples may be studied and the technique can be applied to the neutropenic patient since available neutrophils are concentrated by cytocentrifugation. Clinical evaluation in 443 patients is described.

Excess intravascular coagulation complicating low cardiac output.

In 42 children with congenital heart disease coagulation factor levels were studied serially during the first 20 hours following cardiopulmonary bypass surgery. The acyanotic patients, and also cyanotic patients who survived the operation, showed a progressive improvement in their coagulation profile from initial low postoperative levels. In 12 cyanotic patients who died within 72 hours, however, the coagulation factor levels either remained low, or fell further, until death. Fresh frozen plasma was administered to eight of these patients without apparent benefit. The abnormal coagulation profile correlated significantly with low skin temperature and increased blood loss and was considered to represent excess intravascular coagulation secondary to low cardiac output and poor tissue perfusion.

Coagulation fibrinolysis in sickle-cell disease.

A study of fibrinolytic activity in sickle-cell patients during asymptomatic periods has shown a normal fibrinolytic response to exercise and local heat to the arm. During vasoocclusive crises there was no significant decrease in fibrinolytic activity. These results contrast with earlier reports of decreased fibrinolysis during crisis and a suggestion that fibrinolytic activators might be of value in preventing vasoocclusive episodes. Patients in painful crisis showed a significant rise in fibrinogen concentration and fall in platelet count. The former may contribute to localized vascular sludging by increasing whole-blood viscosity, while the latter probably results from local trapping of platelets in areas of sickling or from subsequent splenic sequestration of damaged platelets. There was no evidence of disseminated, as opposed to localized, intravascular coagulation during crisis.